Increasing ceftriaxone resistance in Salmonella isolates from a university hospital in Taiwan.

Abstract

OBJECTIVES:

Salmonella infection is a distressing health problem worldwide. This study reports the changing epidemiology of Salmonella infections in Taiwan during 1999-2003, with emphasis on increasing ceftriaxone resistance.

METHODS:

Records of Salmonella clinical isolates in Chang Gung Memorial Hospital during 1999-2003 were reviewed. All isolates were identified and antimicrobial susceptibility determined by standard methods. A total of 22 ceftriaxone-resistant isolates were investigated by PCR sequencing of the bla(TEM), bla(SHV), bla(CTX-M) and ampC genes. Southern-blot hybridization was used to localize the ampC gene. Infrequent-restriction-site PCR was used to genotype these isolates.

RESULTS:

A total of 3635 Salmonella isolates, including 3592 (98.8%) non-typhoid Salmonella, were identified. Serogroup B (55.6%) remained the most predominant, but the prevalence has been decreasing. In contrast, serogroup D infections have increased significantly from 13.6 to 22.8%. Overall resistance to ampicillin and chloramphenicol remained high, with the highest rate (91% to both drugs) observed in Salmonella enterica serotype Choleraesuis in 2003. A sudden upsurge of ciprofloxacin resistance from zero to 69% was found in S. Choleraesuis. Ceftriaxone resistance increased in several serogroups (0.8-2.1%; average, 1.5%). The resistance was associated with plasmid-mediated bla(CMY-2) in 14 cases and extended-spectrum beta-lactamases (ESBLs), including CTX-M-3 (n=6), SHV-2a (n=1) and SHV-12 (n=1), in others. Diverse serotypes and genotypes were found among the ceftriaxone-resistant isolates.

CONCLUSIONS:

Increasing ceftriaxone resistance in non-typhoid Salmonella appears to link to the spread of plasmid-mediated ampC or ESBL genes. Effective measures should be taken to prevent the problem worsening.

• Authors: Lin-Hui Su, Tsu-Lan Wu, Ju-Hsin Chia, Chishih Chu, An-Jing Kuo, Cheng-Hsun Chiu
• Journal: The Journal of antimicrobial chemotherapy (J Antimicrob Chemother) Vol. 55 Issue 6 Pg. 846-52 (Jun 2005) ISSN: 0305-7453 [Print] England
• PMID: 15872047 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Anti-Bacterial Agents
• Bacterial Proteins
• Ceftriaxone
• AmpC beta-lactamases
• beta-Lactamases

Topics

• Adolescent
• Adult
• Age Distribution
• Anti-Bacterial Agents (pharmacology)
• Bacterial Proteins (genetics)
• Ceftriaxone (pharmacology)
• Child
• Child, Preschool
• Drug Resistance, Bacterial
• Humans
• Infant
• Infant, Newborn
• Microbial Sensitivity Tests
• Salmonella (drug effects, enzymology)
• beta-Lactamases (genetics)